Application of biofiltration to the degradation of hydrogen sulfide in gas effluents.

A laboratory scale bioreactor has been designed and set up in order to degrade hydrogen sulfide from an air stream. The reactor is a vertical column of 7 litre capacity and 1 meter in height. It is divided into three modules and each module is filled with pellets of agricultural residues as packing bed material. The gas stream fed into the reactor through the upper inlet consists of a mixture of hydrogen sulfide and humidified air. The hydrogen sulfide content in the inlet gas stream was increased in stages until the degradation efficiency was below 90%. The parameters to be controlled in order to reach continuous and stable operation were temperature, moisture content and the percentage of the compound to be degraded at the inlet and outlet gas streams (removal or elimination efficiency). When the H2S mass loading rate was between 10 and 40 g m(-3) h(-1), the removal efficiency was greater than 90%. The support material had a good physical performance throughout operation time, which is evidence that this material is suitable for biofiltration purposes.

Comparison between acarbose, metformin, and insulin treatment in type 2 diabetic patients with secondary failure to sulfonylurea treatment.

The purpose of this study was to determine the most suitable treatment for Type 2 (non-insulin-dependent) diabetic patients with secondary failure to sulfonylureas (SFS). In a four-month comparative study, 36 Type 2 diabetic patients given SFS were allocated to three treatment groups: A (n = 12, M/F 6/6, HbAlc 9.1 +/- 1.6%) received 0.3 IU/Kg body weight (BW) of insulin-Zn between 10 and 11 p.m.; B (n = 12, M/F 6/6, HbAlc 9.2 +/- 1.6%) SFS plus 850 mg/day of metformin; and C (n = 12, M/F 6/6, HbAlc 9.5 +/- 2.4%) SFS plus acarbose 3 x 100 mg daily. Modifications in HbAlc, BW, blood pressure (BP), lipoprotein profile and insulin sensitivity were evaluated. HbAlc decreased in the three groups (A: 17.9 +/- 13.5%; B: 18.2 +/- 4.5%; C: 7.6 +/- 16.8%; all p < 0.05; A and B vs C = p < 0.05). BW increased in group A and decreased in the other groups. BP decreased statistically in group B. HDL-cholesterol increased (1.26 +/- 0.46 vs 1.49 +/- 0.36 mmol/L; p < 0.05) and triglyceride levels decreased (1.68 +/- 0.85 vs 1.16 +/- 0.43 mmol/L; p < 0.05) in group A. There were no significant changes in the other studied parameters. We conclude that, for Type 2 diabetic patients given SFS, both insulin and metformin plus SFS provided better glycaemic control than acarbose plus SFS. Metformin combined with SFS offered further advantages for the control of BW and BP.

Insulin receptor tyrosine kinase activity is reduced in monocytes from non-obese normoglycaemic insulin-resistant subjects.

Insulin sensitivity has been quantified by i.v. insulin tolerance test (0.1 U/kg of body weight) in 18 (11 male/7 female) non-obese (body mass index range 19-25 kg/m2) normoglycaemic subjects. We then compared the tyrosine kinase activity and internalization of insulin receptor in monocytes from the six most insulin-sensitive (group 1) and the six most insulin-resistant (group 3) subjects. Tyrosine kinase activity was measured on immunopurified receptors using 32P-ATP and poly-glutamic acid 4: tyrosine 1, sodium salt (poly-glu-tyr 4:1). Insulin internalization was studied by incubating cells with 1 nmol/l 125I-insulin and measuring total cell-bound and intracellular 125I-insulin by an acid dissociation procedure. Basal (in the absence of insulin) receptor kinase activity was similar in both groups. Maximal (in the presence of 100 nmol/l insulin) kinase activity was 41% lower in group 3 (13.8 +/- 3.6 fmoles 32P-ATP incorporated vs 23.3 +/- 4.0, p = 0.1). Delta increment of receptor kinase activity after insulin stimulation (calculated by subtracting basal from maximal activity) was significantly (p < 0.05) reduced in group 3 (21.3 +/- 3.8 vs 11.1 +/- 2.1) and significantly (p < 0.05) correlated to the in vivo insulin sensitivity. Both total cell-bound (0.70 +/- 0.09% of total radioactivity added vs 0.83 +/- 0.15) and intracellular (0.39 +/- 0.05 vs 0.44 +/- 0.09) 125I-insulin were similar in the two groups. These data suggest that in non-obese, normoglycaemic subjects a defective insulin receptor tyrosine kinase activity may contribute to the development of insulin resistance.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypergonadotropinemia not associated to ovarian failure and induced by factors interfering in radioimmunoassay.

Unexpectedly high LH and FSH serum levels, measured by conventional RIA methods employing a rabbit antibody, were observed in eight women 18 to 34 years of age who came to our observation for acne and/or hirsutism and with no sign of premature ovarian failure. Reinvestigation of patient histories revealed that all of them had previously received multiple injections of a multimicrobial vaccine containing rabbit proteins. Luteinizing hormone and FSH were remeasured by IRMA and ELISA. These techniques revealed that serum levels of both gonadotropins were within the normal range in all subjects. We believe that falsely elevated gonadotropin levels were induced by the presence of heterophilic antibodies against rabbit serum interfering in the conventional RIA.

Ovulation monitored by serum 17 beta-estradiol and ultrasound: differential ovarian response to human gonadotropins in various anovulatory states.

Ovulation induction with human gonadotropins (hMG or pFSH and hCG) was simultaneously monitored with daily serum 17 beta-estradiol measurements and ultrasound in 38 infertile women. They were subgrouped as follows: A, hypogonadotropic hypogonadism (n. 7); B, polycystic ovary syndrome (n. 13); C, non-PCO chronic anovulation (n. 6); D, unexplained infertility (n. 12). The dose of hMG and the duration of therapy were assessed individually depending on the results of the monitoring when serum estradiol concentration was 500-1500 pg/ml and/or ultrasound showed of a follicle of at least 18 mm, hMG was stopped and hCG was administered 36 hours later. Ovulation was obtained in 61 cases and pregnancy occurred in 12 women out of 64 monitored cycles. The highest pregnancy rate was observed in hypogonadotropic hypogonadism; this group also required the greatest total dose of hMG to obtain ovulation. We confirm that women with PCOS are at increased risk with this therapy, since 5 subjects in our series showed signs of ovarian hyperstimulation in spite of the lowest total dose of FSH administered to this group. We conclude that anovulatory states of various origin are associated with different ovarian sensitivity.